IABSD.fr/src/libexec/ftpd/popen.c

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• Author : jan
  Date : 2020-01-15 22:06:59
  Hash : bca58876
  Message : Simplify globbing of ftpd(8)s list and nlst commands. Also avoid command option injection for ls(1). OK martijn@

• libexec/ftpd/popen.c

• /*	$OpenBSD: popen.c,v 1.29 2020/01/15 22:06:59 jan Exp $	*/
  /*	$NetBSD: popen.c,v 1.5 1995/04/11 02:45:00 cgd Exp $	*/
  
  /*
   * Copyright (c) 1988, 1993, 1994
   *	The Regents of the University of California.  All rights reserved.
   *
   * This code is derived from software written by Ken Arnold and
   * published in UNIX Review, Vol. 6, No. 8.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   */
  
  #include <sys/types.h>
  #include <sys/wait.h>
  
  #include <errno.h>
  #include <glob.h>
  #include <limits.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <unistd.h>
  
  #include <netinet/in.h>
  
  #include "monitor.h"
  #include "extern.h"
  
  /*
   * Special version of popen which avoids call to shell.  This ensures no one
   * may create a pipe to a hidden program as a side effect of a list or dir
   * command.
   */
  
  FILE *
  ftpd_ls(const char *path, pid_t *pidptr)
  {
  	char *cp;
  	FILE *iop;
  	int argc = 0, pdes[2];
  	pid_t pid;
  	char **pop, *argv[_POSIX_ARG_MAX];
  
  	if (pipe(pdes) == -1)
  		return (NULL);
  
  	/* break up string into pieces */
  	argv[argc++] = "/bin/ls";
  	argv[argc++] = "-lgA";
  	argv[argc++] = "--";
  
  	/* glob that path */
  	if (path != NULL) {
  		glob_t gl;
  
  		memset(&gl, 0, sizeof(gl));
  		if (glob(path,
  		    GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE|GLOB_LIMIT,
  		    NULL, &gl)) {
  			fatal ("Glob error.");
  		} else if (gl.gl_pathc > 0) {
  			for (pop = gl.gl_pathv; *pop && argc < _POSIX_ARG_MAX-1;
  			    pop++) {
  				argv[argc++] = strdup(*pop);
  				if (argv[argc - 1] == NULL)
  					fatal ("Out of memory.");
  			}
  		}
  		globfree(&gl);
  	}
  	argv[argc] = NULL;
  
  	iop = NULL;
  
  	switch (pid = fork()) {
  	case -1:			/* error */
  		(void)close(pdes[0]);
  		(void)close(pdes[1]);
  		goto pfree;
  		/* NOTREACHED */
  	case 0:				/* child */
  		if (pdes[1] != STDOUT_FILENO) {
  			dup2(pdes[1], STDOUT_FILENO);
  			(void)close(pdes[1]);
  		}
  		dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
  		(void)close(pdes[0]);
  		closelog();
  
  		extern int optreset;
  		extern int ls_main(int, char **);
  
  		/* reset getopt for ls_main */
  		optreset = optind = 1;
  		exit(ls_main(argc, argv));
  	}
  	/* parent; assume fdopen can't fail...  */
  	iop = fdopen(pdes[0], "r");
  	(void)close(pdes[1]);
  	*pidptr = pid;
  
   pfree:
  	for (argc = 3; argv[argc] != NULL; argc++)
  		free(argv[argc]);
  
  	return (iop);
  }
  
  int
  ftpd_pclose(FILE *iop, pid_t pid)
  {
  	int status;
  	pid_t rv;
  	sigset_t sigset, osigset;
  
  	(void)fclose(iop);
  	sigemptyset(&sigset);
  	sigaddset(&sigset, SIGINT);
  	sigaddset(&sigset, SIGQUIT);
  	sigaddset(&sigset, SIGHUP);
  	sigprocmask(SIG_BLOCK, &sigset, &osigset);
  	while ((rv = waitpid(pid, &status, 0)) == -1 && errno == EINTR)
  		continue;
  	sigprocmask(SIG_SETMASK, &osigset, NULL);
  	if (rv == -1)
  		return (-1);
  	if (WIFEXITED(status))
  		return (WEXITSTATUS(status));
  	return (1);
  }